290 THOS. H. MONTGOMERY, 



Other linin threads appeared to connect these granules with the 

 nuclear membrane. The point of importance is that no chromatin 

 granule in the resting nucleus is unattached to a linin thread. In 

 making this statement, I do not mean to state that every granule 

 seen was found in connection with linin ; but the majority can be 

 readily determined to be so connected, and for the others it is al- 

 lowable to assume that their linin connections do not always lie in 

 the plane of the section, and so escape observation. In the prophases 

 of mitosis the chromatin granules become regularly and continuously 

 arranged along the linin threads, so that the linin (all of it?) becomes 

 covered with chromatin (Figs. 3, 4); since the chromatin as we have 

 seen probably forms a continuous long thread, a spirem, we must 

 conclude, I think, that there had existed previously a continuous linin 

 spirem thread. If this be not admitted, it would be difficult to ex- 

 plain the origin of the chromatin spirem. In the rest stage, however, 

 all the chromatin granules need not be placed upon such a continuous 

 linin thread, but some of them very probably could be placed upon 

 side branches of this thread, these side branches then in the pro- 

 phase becoming retracted into the main thread. 



When the chromatin spirem segments into the chromosomes, and 

 this is of great importance for our understanding of later movements 

 of the chromatin elements, the linin thread does not segment but 

 remains continuous, so that connecting every two chromosomes (which 

 were previously in mutual continuity) a delicate linin thread is present, 

 and this is of course continuous with the portion of the thread within 

 the chromosome itself. These inter-chromosomal fibres are very de- 

 licate, and can be seen plainly only by deep staining and then only 

 when they lie exactly in the plane of the section (Figs. 7, 10, 11), so 

 that in most cases they cannot be seen. But since in many cases 

 these connections of the chromosomes can be plainly seen, as in Figs. 6, 

 7, 10, 14, 16 and 21, we can conclude, especially with the consideration 

 of facts to be detailed later, that the linin spirem persists as a con- 

 tinuous thread even after the chromosomes have segmented off and 

 have arranged themselves in the equator of the spindle. Whenever 

 the staining of the preparation is sufficient, and when a careful ad- 

 justment of the light condenser is made so as to bring into view by 

 their refraction the linin elements, then, when a chromosome lies with 

 its long axis in the plane of the section, we find attached to either 

 end of the chromosome a delicate linin fibre; and when these con- 

 ditions are fulfilled, and when further two chromosomes which had 



